Variable speed transmission



P 1934- I c. H. MILLER 1,973,576

VARIABLE SPEED TRANSMI S S ION Filed April 4, 1934 .C /Ya/"ZeSH 77711167" Patented Sept. 11, 1934 1.973.573 VARIABLE SPEED .TRANSMIS ;S ION Charles Henry Miller Chicago Ill.,fassignor to Y i E. H. Sargent &-C o.,-Qhicago, Ill.,.a corporation of Illinois Application April 4, issa serial N nsen 7 Claims. (cra -1,91)"

This invention relates to motor-driven mixers and particularly variable speed mixers suitable for laboratory use.

The main objects of this invention are to pro 5. vide an improved" electric motor-driven mixer having a simple, quickly adjustable arrangement for varying the speed of'rotation'of the mixing shaft;' to provide such a device having a; compact arrangement of few elements; and to provide,

10. such a device having a simple frictional drive "including animproved arrangement for main-. taining contact" between the driving and driven rotating elements;

A specific embodiment of this invention is shown in the accompanying drawing, in which: I Figure 1 is a perspective view of a complete mixing device.

Fig.2 is a sectional view taken on line 2 -2 of Fig. 1 and showing an arrangement for urging the driving and driven elements into engagement with each other. I I

Fig. 3 is a partially, sectioned view taken on line 3-3 of Fig. 2 and showing an arra'nge'mentfor varying the speed of rotation of the driven shaft. i In the, form shown in the drawing, 'myime proved mixer comprises a vertically suspended electric motor 1 having a downwardly projecting driving shaft 2 on which is mounted a coneshaped friction member 3, the surface'of said cone member being tapered downwardly toward the axis of said member and terminatingina 'cylindrical tip 4. p I 1; Projecting outwardly from the casing ofthe motor 1 and fixedly mounted thereon is. am;- porting rod, or arbor 5, which is disposed at one side of the shaft 2 and extends parallelith'ere with. The arbor 5is threaded for substantially its entire length and a hub 6 is pivotally mounted thereon, the hub 6 having a pair of parallelarms 7 which extend laterally therefrom.

Suitably journaled in the arms/1 is a driven shaft 8 which extends outwardly from the arms 7 in a direction parallel to the supporting. IQd arbor 5 and the motor shaft 2.. V V Mounted on theshaft 8 and between the arms 7 is a collar 9 which is keyed to theshaft 8 bya suitable means such as the set screwlil. and above the collar 9is a wheel-shaped frictionmember 11 having a peripheral frictional surfacepre'ferably intheform of a rubber tire- 12. The wheel member 11 is keyed to the. collar 9 by means of lugs or pins 13 on the collar 9 which-exftend into suitable openings in the member -11.

Axial'thrust 'on the shaft 8"is supported by means of a ball bearing 14 disposedbetweenthe collar 9 and the outermost arm 7 and the shaft 8 is provided at its end with a chuck 15 arranged to' hold and: retain a mixing rod 16.

.Thehub 6 is supported on the rod or arbor 5 byImeans of anut 17 disposed in a lateral slot .0. 18 which extends across the axis of the hub 6 and between the arms '1. The nut 17 is preferably' circular in form and provided with a knurled periphery and each face is provided with a shoulder 19 which bears against the adjacent side of. ;.the' slot 18 A headed 'set screw 20', extending througha side of the hub 6 is provided toserve as a'locking means to prevent inadvertent rota'tion'of the nut 17. As shown in Fig. 3, the supporting rod or arbor 5 isprovided with a milled groove or slot 2 1,which extends longitudinally of the arbor 5 for substantially its entirelength and theflhub6 at oneend is provided with a hollow chamber 22, through which the rod or arbor 5 passes or. extends. v

' Disposed within the chamber 22is a spring 23,

preferably of thefspiral coiled clock-spring type, whichissplined to the arbor 5. In the arrange ment 'shownfthe inner end 24 of the spring is bent inwardlytoward the spring axis and seated in the slot or groove 21 and the outer end of the spring issecured to the hub 6 in any suitable manner, such. as hooking the said outer end' of the spring in a slot 25 in the'side wall of the hub 6, the spring being tensioned to normally urge the hub anditsarms pivotally on the arbor 5. The upper endof thechamber ,22 is open to permit assemblingthef'spring 23 therein and a cap 26 is provided to close'off that opening. I vflhe ,injotor "of my improved mixing device is preferably provided with a bracket 2'7 mounted onfthejmo'tor end bell opposite the cone pulley 3. f .'The' device'is then supported on a vertical standardjzshaving' a shiftable lateral arm 29 which extends through an opening in the bracket 27. The arm ,29 is secured to the standard 28 by means ,of alocking screw 30 and thebracket 2'1 is secured'itoi the lateral arm 29 by means of the flockingj,j screw 31. The bracket 27 is- Ialso provided'with ahandle 32 by means of which the mixing device may be held while the arm 29 is being shifted vertically on thestandard28 or the 'bracket27 being shifted laterally on the arm 1 I in operation my 1 improved 'mixing device is mountedsubsta'ntiallyas shown in Figure 1, its vertical height and lateral position being ad- [justed according to the nature of the receptacle '33"and-the"amount' of substance held therein amount alon'g'the groove 22 an The spring 23'is tens'ioned' td urge thehfib 6 pivotally on the arbor 5 and therebyrurge the arms '7, which carry the shaft 8, toward the cone member 3. 5

By varying the axial position of theelineof contact between the tire 12 and the: periphery of the cone member 3, the speed of: rotation of:-

the driven shaft 8 may be a'dji-i'ste'd oven a Wide range.

At the base, or Widest pert ion of: the cone member 3, the speed of the driven shaft 8 is the 8 is the slowest. I H v I The adjustment'forvari i sp ed tithe driven shaft 8 is made "by jfirst ioos nirigtne' locking screw 20 and thenturning thenut 17 so as to shift the hub e, axi'ai y "on'tlief supporting rodorarbor 5. ,As the nut 11? is turned fiOfSl'iiftth --hub 6 on the, rod 5, thep'os'ition jof the ar 12 and wheel 11 is" siiifted' axially relative tofthe cone member 3,and the tire 12 engagesa greater or lesser circumference I the, eone member'fam cordingly' as'its position is shifted up ordown.

Frictional contact between the coneand wheel member's is maintained substantially thesame for all adjustmentsof thearm l along the axis of the arbor 5 by inean spfthe arrangement whereby the spring'23 is. carried with the hub 6 AS the hub iS shiftedfthje, end 'df th spffirig", whichfis seated in the gr eveizz; moves an" equal t re c i s axial distortion of the spring and maintains-a substantiallyiiniform springftensi'on. Througlithetlireaded engagehientoftlfe nut 17 with the arbor or ro 5, any desired amount of wide range of speeds,thatrhight'b eljtransinitted to the shaft 8 is obtainable. Such adjustment is hadwithout any disconnectingof gears and tlie adjustment may even be inadejwithout stopping the motor l f ,1

In the formshown in the drawing, thejcolla'r' il is provided with an annular.peripnera1gi'oove35 which might, if desifed be utilized, drive other rotative devices through the inediiihf er a belt not shown; anda second suchgroove 35.1 is provided adjacent the chuck 15 for' a's'irf ilar'purpqs The binding p sts 36, shown'in Fi ure 1, are for the purpose of supporting,"electrodes, not shown, thatmay be arranged to hang down into the receptacle 33 and the substanc thereinthat is being mixed. I

The principal advantages of H i 1 mg device reside in the simplicityi'ofjtliestructure by which a variationof the speed of rotation of the driven shaft is had; and also inthe arrangenent whereby the speed of thefdriven shaft may be quickly adjusted with a minimum 'ofjefi'o'rt and without the necessity of stopping and then starting the driving 'mote'r', this feature being of considerable; importance in laboratory work where, in certain ,processesfany loss of, time would be a serious handicap .Although but one specific embodiment of this invention is herein shown and des r'iribed} it isto be understood that numerous detailshflthehonstruction shown may be altered or omitted withsliaped friction member on the other of said shafts, said friction members being positioned for engagement with each other, a spring splined to said arbor and arranged to urge said arm toward said-drive shaft, and means to shift said arm along the axis of said arbor.

2'. Thepombination of a. drive shaft, a driven shaft, an arbor parallel with said driven shaft greatest; while at the cylindrical tip 4 of the cone member the speed of rotationgof the shaft and having a longitudinally extending slot, an arm mounted on said arbor and arranged to carry said driven shaft, said" arin being, swingabl'e .on

member on 'one 'o'f said shafts, a wheel-shaped friction member en the other of said shafts, said friction membersbeing positioned for ,"engage j mentwith'each other, a spiral spring having its inner-"end seated insaid'slot and" arranged w ii'rgesa-idarm toward said drive sna ft,""and means to shift saidarm along the axis of said'arbor; the inner' end of said springshifting; along said slot when'sa'id armis shifted. v

3. Thecombination of a drive shaft, a driven ion shaft, anarborparallel" with said driven shaft,

an arm pivotally'inounted onsaid arbor and arranged to carry said driven shaft, said arm being swingable toward, said driveshaft, a 'coneashape'd friction -;nember-"en oneof said shafts,'a wheelshaped'friction member onthefother of said shafts,- said friction members being positioned to engage each other, means normally urging said am towardsaicl drive shaft, and'a nut associated with said arm and having threaded engagement withsaid arbor, saidfnut being arrangedfto be rbtatable independentof said arm and engaged therewith'tog. shiftsaid arm axially on'lsaid-arbor.

4. The' combination of a drive shaft, a driven shaft, an arbor parallel withsaid driven-shaft and having an axially extending slot; an arm arranged to-carry saiddriven shaft and having a hub "pivotally mounted on saidarbor', said arm being swingable toward saiddriveshaft, a cone shaped friction nieniber onohe ofsai'd shafts, a wheel-shaped friction member on the other of said shafts; said friction-members beingpositioned teeng 'gef each other, a' spring'hoiised i'n'said hub and' havingone end seated in said slot and the other end secured to said hub,- said spring being arranged to urge saidarm toward said drive shaft,

and means toshift said hubaxiallyon'said arbor.

'5. A mixing deviceof the class described-comprising'a motor having a projecting shaft and a cone member-fixed on said shaftya supporting rod mounted on "said motor and extending paral l el with the motor "shaft, an ai inhaving a hub "shiftably mounted on said supporting rod, said arm extending laterally from said rod; a driven "snaft'jjpurnai'ed in said arm'and carrying a wheel said'rod an d jas so ciatedlwith said hub to shift the same axially on said, rodlisaid-nut. being arranged to, be rotatable independent of said hub,

conemember to engage saidwheel therewith.

positioned to frictionally'engagelsaid cone m mher, a nut having threaded engagement with ,and means normally urging said arm toward said 6. A mixing device of the class described, comprising a motor having a projecting shaft carrying a friction member fixed thereon, an arbor mounted on said motor and extending parallel with the motor shaft, said arbor having a longitudinally extending groove, an arm mounted on said arbor and extending laterally therefrom, a driven shaft journaled in said arm, a friction member fixed on said driven shaft and positioned to engage the first-named friction member whereby said driven shaft is rotated, one of said friction members being cone-shaped and the other wheel-shaped, a spiral spring having its inner end seated in the groove in said arbor and arranged to urge said arm pivotally on the axis of said arbor and toward the motor shaft, and means arranged to shift said arm along the axis of said arbor to vary the axial location of the line on which said wheel-shaped friction member contacts the periphery of said cone-shaped friction member.

7. A mixing device of the class described, comprising a motor having a projecting drive shaft,

a rod extending parallel with the drive shaft and having a longitudinal groove in its peripheral surface, an arm having a hub pivotally mounted on said rod, said hub having a hollow chamber through which said rod extends, a driven shaft journaled in said arm, a cone-shaped friction member on one of said shafts, a wheel-shaped friction member on the other of said shafts, said friction members being positioned to engage each other whereby said driven shaft is rotated, a spring disposed within said chamber, one end of said spring being seated in the groove in said rod and the other end being secured to said hub, said spring being tensioned to pivotally urge said arm toward said cone pulley, and means arranged toshift said hub along the axis of said rod to axially shift the relative positions of said friction members and thereby vary the ratio of the periphery of said wheel member and the periphery of said cone member at the line of contact of said wheel and said cone member.

CHARLES HENRY MILLER. 

